Cellular therapy for repair of cardiac damage after acute myocardial infarction

Preconditioning diabetic mesenchymal stem cells with myogenic medium increases their ability to repair diabetic heart

INTRODUCTION

Mesenchymal stem cells (MSCs) have the potential for treatment of diabetic cardiomyopathy; however, the repair capability of MSCs declines with age and disease. MSCs from diabetic animals exhibit impaired survival, proliferation, and differentiation and therefore require a strategy to improve their function. The aim of the study was to develop a preconditioning strategy to augment the ability of MSCs from diabetes patients to repair the diabetic heart.

METHODS

Diabetes was induced in C57BL/6 mice (6 to 8 weeks) with streptozotocin injections (55 mg/kg) for 5 consecutive days. MSCs isolated from diabetic animals were preconditioned with medium from cardiomyocytes exposed to oxidative stress and high glucose (HG/H-CCM).

RESULTS

Gene expression of VEGF, ANG-1, GATA-4, NKx2.5 MEF2c, PCNA, and eNOS was upregulated after preconditioning with HG/H-CCM, as evidenced by reverse transcriptase/polymerase chain reaction (RT-PCR). Concurrently, increased AKT phosphorylation, proliferation, angiogenic ability, and reduced levels of apoptosis were observed in HG/H-CCM-preconditioned diabetic MSCs compared with nontreated controls. HG/H-CCM-preconditioned diabetic-mouse-derived MSCs (dmMSCs) were transplanted in diabetic animals and demonstrated increased homing concomitant with augmented heart function. Gene expression of angiogenic and cardiac markers was significantly upregulated in conjunction with paracrine factors (IGF-1, HGF, SDF-1, FGF-2) and, in addition, reduced fibrosis, apoptosis, and increased angiogenesis was observed in diabetic hearts 4 weeks after transplantation of preconditioned dmMSCs compared with hearts with nontreated diabetic MSCs.

CONCLUSIONS

Preconditioning with HG/H-CCM enhances survival, proliferation, and the angiogenic ability of dmMSCs, augmenting their ability to improve function in a diabetic heart.

Endothelial progenitor cells in cardiovascular disease and hypoxia--potential implications to obstructive sleep apnea

In recent years, endothelial progenitor cells (EPCs) have gained a central role in vascular regeneration and endothelial repair capacity through angiogenesis and restoring endothelial function of injured blood vessels. These bone-marrow-derived cells are capable of promoting neovascularization, improving blood perfusion, and facilitating the recovery of ischemic tissues through differentiation into functional endothelial cells and secretion of angiogenic mediators. Obstructive sleep apnea (OSA) syndrome is characterized by recurrent episodes of intermittent hypoxia (IH), which can lead to endothelial dysfunction, atherosclerosis, as well as cardiovascular morbidity and mortality. However, IH also may contribute to cardioprotection and the development of collateral vessels by mobilizing progenitor cells to the circulation and damaged myocardium. Accumulating evidence in recent years suggests that EPCs are decreased in patients with endothelial dysfunction and underlie an increased risk for cardiovascular morbidity in OSA. The current review highlights the potential role of EPCs in the pathogenesis of vascular diseases that is pertinent to OSA.